Paul Gustard was, by his own admission, an average player. He says he could not pass and could hardly catch.

He did, however, win four titles in five years in the back row of a great Leicester squad. He also won the Heineken Cup, captained England Under-21s, and came close to the World Cup squad in 1999.

So I will let you make up your own mind about whether he really was an average player. But he is right about the fact that he could not catch or pass.

It certainly limited his options, even if it did not limit his impact, because he worked out what he loved best about rugby.

He liked to drain his body of every ounce of effort in every game he played. He wore his heart on his sleeve, hunted down every ball, made every tackle, had a quick smile and a hard edge, and understood his role in the team.

His mission in life was to go and make life hard for the opposition, to get in their faces. He also was very happy to make life hard for his own team-mates in training, start the odd fight and make people be better by getting right up in their grille.

He was not afraid to demand the best of others and if your standards slipped, there was a hard tackle to remind you to be on your game. It was a simple philosophy that has lived on into his coaching career.

Paul is now the defensive brain behind Saracens, who have conceded the fewest points – 260 – in the Premiership this season.

That is testament to his ability, not least because the best coaches are able to take the complicated and make it seem easy. Remove the grey areas and there is clarity.

His plan is almost comic in its simplicity: get in a line, spread three metres apart – if you are close to the ruck then stay a fraction closer to shut out darting scrum-halves and close quarter heavy runners – watch the ball, and when the opposition release it, move forward quickly, together, and smash the area in and around the ball, preferably in twos. Brutal. Simple. Fun.

Where the shift has come is in the fact that he has everyone watching the ball. I used to think that was a recipe for disaster.

Teams who sat on their heels and watched the ball were done for; the old-fashioned sliding, drifting system got pulled apart with ball watchers in the defensive line.

You needed to push players out towards the touchline, bums facing infield and trusting the players on your inside.

Ball watchers tended to be much squarer on, and the drift system could not cope as you either ran into each other or headed in different directions.

Gustard believes in unity, but in completely the opposite way to before. He wants everyone to be a ball watcher.

This way, the team can still move as one, and you can see the defenders on the inside as they move up in your line of vision.

This way you work with them. Watch the ball, move up together, smother everything. It works for the professionals, and it works for the amateurs.

Two weeks ago at Moseley Oak Rugby Club, Gustard ran a training session for the side Scott Quinnell and I put together for our television programme School Of Hard Knocks.

Our scratch XV were approaching their final game and we needed a hand getting them fired up for their defensive duties.

They like having the ball, but they do not necessarily like to tackle. Some look allergic to it.

An hour and a half with Gustard had them thinking differently. I watched it happen – from lambs to lions in 90 minutes.

It was quite stunning to watch. I used the same session on the Marlow Under-10s a week later and saw a dramatic improvement.

So what is Gustard’s secret? Simply put, he has managed to inject his view of defence as the fun part of the game.

Attack was never his forte, so he created the ‘wolf pack’ mentality. The Marines have a similar thought when they say that the strength of the wolf is the pack and the strength of the pack is the wolf.

Hunt together, go as one, and stay connected, and you become powerful.

But you also need individually to be responsible for your role, to cover each other’s backs, and to work hard for each other. You need to trust one another.

Gustard has managed to instil a culture and to put in place a system that means players like him never feel alone.

Especially if they buy into the idea that a “fast line speed covers a multitude of sins”. It is one of Paul’s favourite lines.

Move up slowly and the opposition can dominate contact, can manufacture space. React with a fast line speed and a defence can consume an attack.

This matters because very few players are perfect tacklers on their own. They will eventually make a mistake.

A quick run-through of the Saracens back line show this to be true: Alex Goode can get stepped and beaten for pace; Dave Strettle often resembles a basketball player coming in for an intercept; Chris Ashton gets bumped and bullied; Owen Farrell goes in very upright; Richard Wigglesworth over-commits and loses his centre of gravity.

The exception to the rule is Brad Barritt, but he is a freak – and even he will do something wrong at some point. S

o why allow one person to be isolated? Why give one player too much to do? With the wolf pack you do not have to and it allows weaknesses to be covered up and is the best way with a team, erased by a committed and unified effort.

Gustard has created a system that players buy into, and that is proving as powerful a weapon as quick ball off the top of a line-out.

He calls it “try scoring defence” – defence so powerful that you score tries even when you start without the ball.

Just look at the recent Wembley game against Harlequins, with Ashton and Farrell picking off attacking passes by taking the space, moving forward and dotting down for intercept tries.

But while they have been doing well in the Premiership, Europe has been much tougher for Saracens to dominate physically. Toulouse beat them up, home and away.

They face a huge task on Saturday night against Ulster, who have a massive pack with foreign influence and local lads mixed together.

Where Ulster can cause Saracens problems is with the speed of ball, and Saracens will not be able to get themselves set as well as they would like.

It will be interesting to see how their system of trust holds up, or whether, when the pressure really comes on, they start to have doubts, and gaps begin to appear.

What is not in doubt is that the game is the sort that Gustard used to live for. It gave him the chance to show ‘better’ rugby stars just how difficult life could be and you can be sure his current pack of players will not let him down.

Saracens will go to Ravenhill and play, but you get the sense that to prevail the wolf pack will have to be wild and possessed. And preferably cross-eyed.

I say this in great seriousness. Ball watching is at its best when the opposition have slow ball, Saracens can generate slow ball in the Premiership.

Get set, having dominated contact, watch the ball, move forward. But in Europe it is different. There is more power. There is more pace.

Ulster can and will generate some quick ball. They will win contact. Saracens will not be able to get set as well as they would like.

That is when they must become cross-eyed. Watch the ball, still move as one, trust the system, but also keep an eye looking for width, pace and numbers.

There will be times when they will have to head to the touchlines to deny tries, relentlessly going forward will only see them picked off.

The cross-eyed wolf pack can go to Ravenhill without fear. They will go as underdogs. But they will not go with fear.